/*  fit the HCV data using the nlinmix macro  */

options ps=59 ls=80 nodate; run;

/*  include the macro from file nlinmix.sas */

%inc 'nlinmix_macro.sas'  / nosource;

data hcv;  infile "hcvmix.dat";
  input id days vl;
run;

%nlinmix(data=hcv,
    model=%str(
     v0=exp(beta1+b1);
     cc=exp(beta2+b2);
     e=exp(beta3+b3);
     t0=0.2; 
     dd=0;
     if days>t0 then dd=1;
     tt = dd*(days-t0);
     predv = v0*(1-e+e*exp(-cc*tt));
  ),
  derivs=%str(
     d_beta1 = predv;
     d_beta2 = -v0*e*exp(-cc*tt)*cc*tt;
     d_beta3 = v0*e*(exp(-cc*tt)-1);
     wt=1/(predv*predv);
  ),
  parms=%str(beta1=1.5 beta2=1.5 beta3=-0.15),
  stmts=%str(
     class id;
     model psuedo_vl = d_beta1 d_beta2 d_beta3 / noint notest solution;
     random d_b1 d_b2 d_b3 / subject=id type=un solution;
     weight wt;
  ), 
  expand=eblup,
  procopt=%str(empirical method=ml)
)